Autopostback=true

Hi,

I have a radio button list which gets binded from database. 

I have 

<asp:UpdatePanel runat="server" ID="updHow"><ContentTemplate><tr ><td ><asp:Label runat="server"  ID="lblHow" Text="How did you hear about us? " ></asp:Label><br /><br /></td><td ><asp:RadioButtonList ID="rblHow" runat="server" AutoPostBack="true" OnSelectedIndexChanged="rblHow_SelectedIndexChanged">                         </asp:RadioButtonList><telerik:TextBox ID="radHowOther" runat="server" visible="false"></telerik:RadTextBox><br /><br />              </td></tr>
</ContentTemplate>
</asp:UpdatePanel>

In my selected indexed changed I have

If rblHow.SelectedItem.Value = "Other" Then
radHowOther.Visible = True
Else
radHowOther.Visible = False
End If

When I have this code, Although I have the update panel around my radio button list when ever I change the selection whole page is getting blinked.  How can I stop that??

I dont wnat the user to feel that page is being loaded again.

Thanks